Year-round observations of carbon biomass and flux variability in the Southern Ocean

Three Carbon Explorer (CE) floats profiling to kilometer depths in the Southern Ocean tracked dawn-dusk variations of mixing/stratification, particulate organic carbon (POC), and light scattering and sedimentation at 100, 250, and 800 m continuously from January 2002 to April 2003. Data were analyzed in conjunction with contemporaneous satellite winds and chlorophyll and derived subsurface light fields. The CE deployed at 66{sup o}S 172{sup o}W operated in the ice edge zone in absence of light. Two CEs deployed at 55{sup o}S 172{sup o}W recorded wintertime mixing to {approx}400 m, yet observed very different bloom dynamics and sedimentation the following spring. Four hypotheses are explored. The strongest is that shallow transient stratification of the deep winter mixed layer to shallower than photosynthetic critical depth occurred more frequently in the non-bloom/higher sedimentation case. The lower particle export to 800 m under the bloom was hypothesized to be due to higher interception of sinking carbon by a relatively starved over wintering zooplankton population. In the Southern Ocean surface phytoplankton biomass may counter indicate particle flux at kilometer depths

Particulate matter chemistry and dynamics in the Twilight Zone at VERTIGO ALOHA and K2 Sites

Understanding particle dynamics in the 'Twilight Zone' is critical to prediction of the ocean's carbon cycle. As part of the VERTIGO (VERtical Transformations In the Global Ocean) project, this rarely sampled regime extending from the base of the euphotic layer to 1000 m, was characterized by double-paired day/night Multiple Unit Large Volume in-situ Filtration System (MULVFS) deployments and by {approx}100 high-frequency CTD/transmissometer/turbidity sensor profiles. VERTIGO studies lasting three weeks, contrasted oligotrophic station ALOHA (22.75{sup o}N 158{sup o}W), sampled in June-July 2004, with a biologically productive location (47{sup o}N 161{sup o}E) near station K2 in the Oyashio, occupied July-August 2005. Profiles of major and minor particulate components (C{sub org}, N, P, Ca, Si, Sr, Ba, Mn) in <1, 1-51, and >51 {micro}m size fractions, in-water optics, neutrally buoyant sediment trap (NBST) fluxes, and zooplankton data were intercompared. MULVFS total C{sub org} and C-Star particle beam attenuation coefficient (C{sub P}) were consistently related at both sites with a 27 {micro}M m{sup -1} conversion factor. 26 At K2, C{sub P} profiles further showed a multitude of transient spikes throughout the water column and spike abundance profiles closely paralleled the double peaked abundance profiles of zooplankton. Also at K2, copepods contributed {approx}40% and 10%, night and day, respectively to >51 {micro}m C{sub org} of MULVFS samples in the mixed layer, but few copepods were collected in deeper waters; however, non-swimming radiolarians were quantitatively sampled. A recent hypothesis regarding POC differences between pumps and bottles is examined in light of these results. Particulate >51 {micro}m C{sub org}, N, and P at both ALOHA and K2 showed strong attenuation with depth at both sites. Notable at ALOHA were unusually high levels of >51 {micro}m Sr (up to 4 nM) in the mixed layer, a reflection of high abundances of SrSO{sub 4} precipitating Acantharia. Notable at K2 were major changes in water column inventories of many particulate components to 700 m over 10 days. Carbon mass balance, with the consideration of particle inventory changes included, indicated that over 98% and 96% of primary produced C{sub org} was remineralized shallower than 500 m at ALOHA and K2, respectively. Production of CaCO3 was estimated to be {approx}0.06, 0.89 and 0.02 mmols m{sup -2} d{sup -1} at ALOHA and at K2 during two separate week long study periods, respectively. Similarly, Si production was estimated to be {approx}0.08, 10.7, and 4.2 mols m{sup -2} d{sup -1}. An estimated 50% and 65% of produced Si was remineralized by 500m at ALOHA and K2, respectively. Little carbonate dissolution was seen in the upper 500 m at ALOHA, a reflection of 400% super saturation of surface waters and the 700 m deep saturation horizon. Over 92% of produced CaCO{sub 3} was dissolved shallower than 500 m at K2 and biological enhancement of dissolution was readily apparent in waters above the 200 m calcite saturation horizon

Caesarean Section rates in South Asian cities: Can midwifery help stem the rise?

Introduction: Caesarean section (CS) is a life-saving surgical intervention for delivering a baby when complications arisein childbirth. World Health Organization recommends a rate of CS from 10% to 15%. However, CS rates increased steadily in recent decades and have almost doubled from 12.1% in 2000 to 21.1% in 2015. Therefore, this has become a global public health problem. The main purpose of the scoping review article is to give an overview and analysis of the rising CS use in four South Asian countries: Bangladesh, India, Nepal and Pakistan. Methods: A scoping review was carried-out using several bibliographic electronic databases (MEDLINE, EMBASE, SCOPUS, CINAHL and Web of Science), organizational websites and open access journal databases. Literature was searched from December 2011 to December 2018 for articles reporting hospital-based CS rates.Inclusion criteria were primary studies conducted ininstitutional setting in Bangladesh, India, Nepal and Pakistan and published in the English language. Results: We have included 43 studies. Together these studies show that the rate of CS is increasing in all four countries: Nepal, Bangladesh, Pakistan and India. However, this isuneven with very low rates in rural and very high rates in urban settings, theco-existence of ‘Too Little Too Late & Too Much Too Soon’. Hospital based studies have shown that the CS rate is higher in urban and private hospitals. Age, education andsocio-economic status of women, urban residence and distance from health facility are associated with CSs. CS is higher among highlyeducated affluent urban women in private hospitals in South Asian Countries. Conclusion: Rising CS rates in South Asian cities, particularly in specific groups of women, present a challenge to hospital staff and managers and policy-makers. The challenge is to avoid ‘Too Much Too Soon’ in otherwise healthy urban women and avoid ‘Too Little Too Late’ in women living in remote and rural area and in poor urban women

Factors contributing to rising cesarean section rates in South Asian countries: A systematic review

Rising cesarean section (CS) rates are a global public health problem. The systematic review investigates key indications for performing CS and factors significantly associated with the rising rate of CS in South Asia. Primary studies in South Asia published between January 2010 and December 2018 were searched using relevant electronic databases: MEDLINE, Scopus, PubMed, Web of Science, CINAHL, NepJOL, and BanglaJOL. A narrative synthesis of the indications for performing CS and factors significantly associated with the rising CS rates was performed using content analysis. A total of 68 studies were included in this review. The most common medical indication for CS was fetal distress, followed by previous CS, antepartum hemorrhage (including placenta previa/abruption), cephalopelvic disproportion, failed induction, hypertensive disorders in pregnancy, oligohydramnios, and non-progress of labor. Maternal request was the most common non-medical indication for conducting CS. Higher maternal age was the most common significant factor associated with the rising CS rate followed by higher maternal education, urban residency, higher economic status, previous CS, pregnancy/childbirth complications, and lower parity/nulliparity. Preference for CS and increasing private number hospital were also factors contributing to the rising rate. Several key indicators and factors significantly associated with rising CS rate are revealed. These key indicators and significant factors reflect the global trend. Reduction in the use of primary CS, unless medically warranted, would help stem rates of CS. Realistic and candid explanation to pregnant women and their families regarding the benefits of vaginal birth for women and babies should form an integral part of maternity care as these are issues of public health

A brief history and indications for cesarean section

Cesarean section (CS) is one of the oldest surgical operations. Originally,this surgery was performed post-mortem by cutting open the woman’s abdomen to remove a dead or alive fetus. It was therefore not intended for saving the mother in ancient times. Roman law and religious rituals shaped the procedure until the Middle Ages. At that time, the indication of CS was only post-mortem. Although CS became a medical procedure in the Renaissance, maternal mortality was extremely high, mainly due to hemorrhage and puerperal infection. The reason for performing CS was to rescue the mother and fetus from protracted labor as a last resort. Since the late 19th century, with the introduction of chloroform and the developments of surgical techniques, and the availability of blood transfusion in the early twentieth century, CS became a relatively safe procedure, further helped by the introduction of antibiotics after World War II. Then, CS was increasingly an intervention to preserve the health and safety of both mother and fetus. During the 21st century, CS has been performed even without medical indication, such as maternal choice. Advancement of obstetric practice technologically and professionally during the period as well as changing attitudes of both obstetricians and childbearing women meant indications for CS are no longer limited to medical/obstetric indications. CS is perceived as a safer mode of childbirth. Therefore, the indications of CS have been changed drastically from ancient times (rescuing a baby from dying or dead mother) to the 21st century (maternal choice/reproductive rights)

Orbital Separation Amplification in Fragile Binaries with Evolved Components

The secular stellar mass-loss causes an amplification of the orbital separation in fragile, common proper motion, binary systems with separations of the order of 1000 A.U. In these systems, companions evolve as two independent coeval stars as they experience negligible mutual tidal interactions or mass transfer. We present models for how post-main sequence mass-loss statistically distorts the frequency distribution of separations in fragile binaries. These models demonstrate the expected increase in orbital seapration resulting from stellar mass-loss, as well as a perturbation of associated orbital parameters. Comparisons between our models and observations resulting from the Luyten survey of wide visual binaries, specifically those containing MS and white-dwarf pairs, demonstrate a good agreement between the calculated and the observed angular separation distribution functions.Comment: 37 pages, 13 figure

Atmospheric Heating and Wind Acceleration: Results for Cool Evolved Stars based on Proposed Processes

A chromosphere is a universal attribute of stars of spectral type later than ~F5. Evolved (K and M) giants and supergiants (including the zeta Aurigae binaries) show extended and highly turbulent chromospheres, which develop into slow massive winds. The associated continuous mass loss has a significant impact on stellar evolution, and thence on the chemical evolution of galaxies. Yet despite the fundamental importance of those winds in astrophysics, the question of their origin(s) remains unsolved. What sources heat a chromosphere? What is the role of the chromosphere in the formation of stellar winds? This chapter provides a review of the observational requirements and theoretical approaches for modeling chromospheric heating and the acceleration of winds in single cool, evolved stars and in eclipsing binary stars, including physical models that have recently been proposed. It describes the successes that have been achieved so far by invoking acoustic and MHD waves to provide a physical description of plasma heating and wind acceleration, and discusses the challenges that still remain.Comment: 46 pages, 9 figures, 1 table; modified and unedited manuscript; accepted version to appear in: Giants of Eclipse, eds. E. Griffin and T. Ake (Berlin: Springer

Stellar activity cycles and contribution of the deep layers knowledge

It is believed that magnetic activity on the Sun and solar-type stars are tightly related to the dynamo process driven by the interaction between rotation, convection, and magnetic field. However, the detailed mechanisms of this process are still incompletely understood. Many questions remain unanswered, e.g.: why some stars are more active than others?; why some stars have a flat activity?; why is there a Maunder minimum?; are all the cycles regular? A large number of prox- ies are typically used to study the magnetic activity of stars as we cannot resolve stellar discs. Recently, it was shown that asteroseismology can also be used to study stellar activity, making it an even more powerful tool. If short cycles are not so un- common, we expect to detect many of them with missions such as CoRoT, Kepler, and possibly the PLATO mission. We will review some of the latest results obtained with spectroscopic measurements. We will show how asteroseismology can help us to better understand the complex process of dynamo and illustrate how the CoRoT and Kepler missions are revolutionizing our knowledge on stellar activity. A new window is being opened over our understanding of the magnetic variability of stars.Comment: 7 pages. To appear in Astrophysics and Space Science Proceedings series of the 20th Stellar pulsation conference held in Granada (Spain) from 6 to 10 September 2011

Spatializing the Ecological Leviathan: Territorial Strategies and the Production of Regional Natures

This paper explores a dual absence – the absence of the state within contemporary geographical analyses of nature; and the absence of nature within contemporary explorations of state power. We argue that the modern state continues to play a crucial role in framing social interactions with nature, while nature is still vital to states within their realization of different forms of material and ideological power. In order to reconnect analyses of the state and nature, this paper combines work on the production of nature and state strategy with Lefebvre’s recently translated writings on state space and territory. By focusing on the production of territory (or state space), we explore the interaction of the state and nature in the context of the political management of social and ecological space. We unravel the spatial entanglements of the state and nature through an analysis of the British state’s territorial strategies within the West Midlands region. By considering three key historical periods within the history of the West Mid-lands we reveal how the emergence of the regional space called the West Midlands is a product of the ongoing spatial dialectics of state and nature therein